In the age of micro-blogging it will never be a wise move to bar an outspoken and popular filmmaker from a passenger aeroplane because of his size.

Having done just that to Kevin Smith, who is the director of films such as Clerks and Chasing Amy, Southwest Airlines was forced into hasty public apology after he handed out a severe Twitter-lashing to the airline and mobilised complaints from his 1.64 million followers.

"Wanna tell me I'm too wide for the sky?" Smith asked on his Twitter account shortly after the incident. "Totally cool but fair warning folks: If you look like me, you may be ejected from Southwest."

Smith had fallen victim to Southwest's booking guidelines for a "customer of size" which say that passengers who are unable to lower both armrests when seated should book another seat because of complaints it has received from customers whose comfort has been ruined by the "encroachment of a large seatmate".

Smith used his Twitter account to reveal he was deemed a "safety risk" by the captain of the plane.

"I know I'm fat, but was Captain Leysath really justified in throwing me off a flight for which I was already seated?''

A barrage of tweets condemning the airline for its policy followed, prompting angry customers to share their stories of rejection from Southwest and an apology from the chastened airline.

Aware of the unfolding PR disaster, a tweet appeared on Southwest's Twitter feed about six hours later, promising Smith he would get a call from the airline's customer relations vice-president.

"Again, I'm very sorry for the experience you had tonight. Please let me know if there is anything else I can do," a second tweet to Smith read.

His anger seemingly undiminished, Smith was, last night, still aiming tweets at Southwest's "PR-challenged, fatty-haters. Your apology is insulting, redacted, bullshit" and promised to use his Sunday night podcast to lambast the airline further.

Smith, known for his edgy, expletive-ridden films, was given a seat on a later flight to Burbank and described how he "didn't even need a seat belt extender to buckle up. Somehow, that shit fit over my 'safety concern' creating gut."